A little note: the small 'tsu' at the end of words indicates that the word is being 'cut-off'. You can basically ignore it completely since there isn't really a similar concept in Romance/Germanic languages.(Or not that I know of any) The closest thin would probably be staccato in music.
Even with the translation, I still don't quite get what's going on here. All I got was that Marisa is being held, mouth open, by an anon hand onto Parent Reimu's so the child would end up in Marisa's mouth. Then it just gets sketchy from there.